A simple porous medium is composed of equal nonconduct- ing spheres, the packing of which is cubic, as shown in Fig. 1.32. The pores are filled with a liquid of resistivity Rw. a. Determine the porosity of the rock. b. Calculate the formation resistivity factor of this rock. c. What is the cementation exponent, m, of this rock that would satisfy a relation of the form F=6-m? d. In what type of rock might the m calculated above apply? DIRECTION OF CURRENT FLOW Hint: Resistane of Unit Cell rw Rw d! = 2 4,2 -7(r2 -12) Fig. 1.32-Porous medium of Problem 1.3.